package org.hhchat.others.microsoft;

import java.util.Scanner;

public class microsoft001 {
    static int Q ;
    static int P ;
    static int N ;

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            P = scanner.nextInt();
            Q = scanner.nextInt();
            N = scanner.nextInt();
            System.out.printf("%.2f", getExp(P,N));
        }
    }

    static int getNext(int p) {
        return p + Q >100? 100:(p+Q);
    }

    static double getExp(int p, int i) {
        int failureNextP = getNext(p);
        double dP = p / 100.0;
        double result=0.0;
        if (i == 1) {
            if (failureNextP == 100) {
                result = dP + 2 * (1 - dP);
            } else {
                result = dP + (1 - dP) * getExp(failureNextP, i);
            }
        } else {
            int successNextP = P >> (N-i+1);
            if (p == 100) {
                result = getExp(successNextP, i-1) +1;
            }else {
                result = dP * (getExp(successNextP, i - 1) + 1) + (1 - dP) * (getExp(failureNextP, i) +1);
            }
        }

        return result;
    }
}